Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the front view of a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof;

FIG. 5 is the fifth image thereof;

FIG. 6 is the sixth image thereof; and,

FIG. 7 is the seventh image thereof.

The broken lines shown in the drawings illustrate portions of the display screen or portion thereof with transitional graphical user interface and form no part of the claimed design.

The appearance of the display screen or portion thereof with transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-7. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 